Introduction
I'm back yet again with another exciting development in the world of Solar Jetman glitches. With every TAS I make I keep thinking there won't be any new major glitches found anytime soon, but this game continues to surprise me. I encountered this glitch by complete accident while doing speedrun attempts and pretty soon realized that another TAS was necessary.
The Tether Glitch
This glitch allows the pod to tether an empty entity and entities that are not intended to be carried. It is comparable to the popular stale reference manipulation glitch in Ocarina of Time.
Setup
The trigger for this glitch is a CPU interrupt during the collision handler for the pod and a dropped item from destroying a saucer forcer or a space snake enemy. The interrupt must occur after the entity data that represents the score value of the item is cleared from memory, but before the entity itself is cleared from memory. In this state, the item is now treated as a item that can be carried. One quirk of this glitch is that it requires at least 1 player bullet entity slot to be open out of the 8 available, because the score indicator takes up this slot and the code branch we are targeting for this interrupt only occurs when the score indicator is displayed. A fairly consistent setup has 7 player bullets spawned in and 2-3 enemies spawned in, but as with other glitches involving CPU interrupts there is unpredictable variance that may need to be accounted for. The next stage occurs when the dropped item despawns, or is collected a second time from shooting it with a bullet. The tether does not know that the item has been cleared from memory and remains tethering nothing. The next entity that loads into the same slot in memory that the item took up will then be teleported into the tether and be carried by the pod.
Applications
By loading an entity into the empty slot that the tether points to, important objects can be reached sooner than usual or even through walls because it will warp into the tether as soon as the object is loaded off screen.
Dropping off the item dropped from a saucer forcer can grant a large sum of money. This is known as the lottery glitch. The entity data in memory that is used for other dropped off items to determine the point value is normally used as a timer for the dropped item to keep track of when it should despawn. This means that a different value is rewarded for each frame it could be dropped off. There is not a direct correlation between value and frame count, as the read value is intended to be an index into a table to lookup the value and out of bounds values lead to unpredictable results.
In a pinch, this glitch can be used to gain item tether momentum in place of another item that may be more out of the way than spawning in a saucer forcer or space snake enemy.
On some levels, attempting to perform the tether glitch on a star dropped by a space snake enemy instead treats the star like a wormhole to the part room. It does still require the player to have the necessary fuel cells collected but can be a time save for other categories, even in RTA.
Strategies
While the tether glitch is the premier strategy of this TAS, there are many other sophisticated strategies as described below. Further details of these strategies can be found in the
game resources page.
Warp Duplication
When a bullet makes contact with the warp enemy, a code branch executes to handle the collision. One instruction is responsible for initializing the warp in the persistent entity array in RAM. Another instruction is responsible for clearing the warp enemy from the active entity array. If an interrupt is triggered between these two instructions then the warp will have spawned in and the enemy will continue to be spawned in, thus allowing the enemy to interact with the bullet a second time so that the warp is duplicated.
The planet that the glitched warp transports the player to is determined by its index in the persistent entity array. Planet 1 starts with 6 persistent entities, the intended warp is 7, meaning the glitched warp will transport the player to planet 8. If this glitch is repeated enough times in a row, then a warp directly to planet 12 will be created.
Wall Clipping
Wall clipping is still one of the biggest time saves in this TAS, and comes in a few different flavors. A bump clip occurs when bumping into a corner at a precise angle with high enough speed that hitting one of the walls will bypass collision on the other wall. This run actually features a newly discovered bump clip in a wider angled corner that is only possible when above usual max speed (see tether momentum). Clean clips require a frame perfect shield with pixel precision to bypass collision entirely and phase through the wall, although this tactic only works at the corners of a leftward vertical wall as their collision data seems to be misaligned by one pixel.
Boss Eye Despawn
One of the boss's eyes can be despawned by shooting bullets at the beginning of the auto-scroller section in a peculiar way to trigger a CPU interrupt at just the right time. There is a little more clarity on the specifics of this glitch now. Usually, the large meteors spawn a few smaller meteors when destroyed, and doing so clears out that enemy from list of level enemies and also transforms itself into one of the smaller meteors to reuse the entity slot. If the interrupt happens before the transformation is complete, then on the next frame the meteor will again attempt to remove itself from the list of level enemies, but now using the wrong index which is always incorrectly set to 1, which represents one of the boss eyes. This clarity also confirms that using this method can only ever delete this one boss eye since that index will always be 1.
RNG Manipulation
RNG manipulation is heavy used throughout the run, primarily by using the inputs for player two. Although there is no other use for a second controller, it still influences the game's RNG based randomness. This allows us to nearly perfectly control the RNG state without affecting the inputs for the controller also controlling the player. This edition of the TAS commands the RNG to spawn saucer forcers at desired locations for tether glitches, and also for spawning spheres to setup CPU interrupts.
Tether Momentum
The max speed of the pod is usually 3 pixels per second. However, the momentum from a carried item can push the pods speed up to 4 pixels per second. In order to make this work, the carried item must be consistently in front of the pod and any amount of thrust in a horizontal direction will reset the the speed to 3. This also works in the vertical direction, but when gravity is applied to the pod it again resets back to 3. However, because of the lottery glitch we can afford the anti-gravity item from the shop so that we can bypass this limit.
Wormhole Warping
The lottery glitch also allows us to purchase the Italian Racing Jetpod, which is the majority of the time save for this TAS. This pod unlocks the built in mechanic of warping between small wormholes on each planet, simply by colliding with them. The warping always occurs in a set pattern, and all momentum and tethered items are preserved. One quirk that cannot be observed just through this TAS is that dropping off an item locks out the pod from warping through it until the pod moves away a certain distance from the wormhole, as a safeguard to prevent accidental warping that might be frustrating to the player. This is why we always warp first and then drop off items afterwards.
Route Summary
Planet 1
The first order of business is to grab the shield and return it to the mothership, while simultaneously manipulating the RNG to spawn a saucer forcer. Killing the turret enemy is required as the saucer forcer can only spawn if one of the first 3 enemy slots is open.
Next, we will kill the saucer forcer and perform a bump clip to enter the wall. Bouncing off the leftward wall and turret enemy allow us to get rightward moment faster here.
Then a CPU interrupt occurs to trigger the tether glitch.
More RNG manipulations are setup to spawn in 4 sphere enemies which help setup the CPU interrupt for the warp duplication, which will occur 6 times off screen using a single bullet to spawn in a warp to planet 12.
Another saucer forcer is manipulated to spawn in off screen to the right, just before dropping off the glitched item to trigger the lottery glitch, granting us more than enough money to cover our expenses for this route.
Lastly, we perform another tether glitch on the newly spawned in saucer forcer, which we will use to teleport the planet 12 warp directly onto our tether to enter as fast as possible. By shooting the tethered item to despawn it, the empty slot gets consumed by the newly spawned in warp which then immediately teleports to our tether since it is still pointing at that slot.
The spawning mechanics of saucer forcers are the main time bottleneck of this planet. These enemies will spawn at a 50% rate when the in game timer hits about 13 seconds. This timer resets every time an item is dropped off or a new level starts. This route requires 2 to spawn in. The first one can easily fit in the time it takes to get the shield. The second one, however, actually requires us to slow down a little bit before dropping off the glitched item, but it saves more than enough time by entering the warp faster. So the second half optimizes for having the highest rightward momentum the at the moment the second saucer forcer spawns in, as that is always at a set horizontal distance.
Planet 12
Shop
At the shop, we will purchase anti-gravity, double strength thrusters, and the Italian Racing Jetpod. While we can afford a bullet upgrade, it would not make up any time that we lose from buying it.
Fuel 1
To get to the first fuel quickly, we perform a bump clip northeast of the mothership. Then we grab the fuel and head down to the nearby wormhole by abusing vertical tether momentum. We perform a clean clip to get to the wormhole slight faster. After warping through, the fuel is dropped off.
I played around with an alternate idea to grab the fuel faster using a tether glitch, but the 13 second spawn rule is just a handful of frames too late to save time.
Fuel 2
The second fuel is to the right of the wormhole we warped out of. On the way back after grabbing the fuel, we get leftward tether momentum and clean clip into the wall to get to shortcut to the third fuel. We perform a deceptively tight maneuver to drop off the fuel while remaining out of bounds.
I also attempted to grab this fuel faster using a tether glitch, but it was again just a little to slow. to be useful.
Fuel 3
We shortcut to the third fuel while out of bounds and build up leftward tether momentum before clipping back in bounds and entering the wormhole. We will maintain this tether momentum for the next few sections. After warping, we drop off the fuel.
Fuel 4
We navigate left to the next fuel cell and bump off of the enemy with our shield to perfectly reverse our horizontal speed to maintain tether momentum. Then we grab the fuel and warp to the next wormhole before dropping off this last fuel.
To The Part Room
Since we still have tether momentum, we can perform a new version of the bump clip here that only works when over the normal speed cap. We also perform heavy RNG manipulation to get 2 precise sphere spawns which will be used to set up the next tether glitch. At this point we are still far away from 13 seconds though, so we will use some bullets to push them further downwards so that we can get as far as possible without despawning them. We do have to slow down a little bit to prevent this despawn from occurring. At 13 seconds, the saucer forcer is spawned in and we perform a tether glitch which we will use to teleport the warp to the part room through the wall to avoid going all the way around, which saves about 5 seconds.
Part Room
We quickly navigate to the chest and clip into the wall on the way to skip travelling back upwards over the big hill, which also allows us to build up leftward tether momentum much quicker after grabbing the chest. The chest is then dropped off at the wormhole to trigger the final sequence.
The route for this room is essentially the same as the previous TAS, but with improved movement due to the anti-gravity item, which ignores the gravity of both the level and the mega-gravity planet enemies.
Final Boss
The boss eye despawn glitch is performed at the beginning of the autoscroller section by using bullets to trigger a CPU interrupt at just the right moment. The rest of the autoscroller is just waiting for the boss.
The boss kill is still the same as it has been for the last couple TAS publications, no further speedups have been found. It is worth noting that purchasing the Italian Racing Jetpod does actually have an affect on the Golden Warpship, allowing it to shoot faster when holding down the A button, but it is still the same shooting speed as frame perfect mashing so it does not save any time.
Timing
Criteria
For a more precise timing, the following RAM addresses are referenced:
0x003B - Current Planet Indicator (Planet 1 = 00, Planet 12 = 0B, Part Room = 18, Boss = 1A)
And the following criteria:
- Start - All the frames from power-up until the start of the first planet.
- Planet {#}, Part Room, Boss - These splits start as soon as the planet indicator changes. Since this value is initialized to 00, special case for Planet 1 which starts on the frame pressing START on the "START GAME" menu.
- End - The last frame of input.
|| NEW || OLD || DELTA
_ _ _ _ _ _||_ _ _ _ _ _ _ _||_ _ _ _ _ _ _ _||_ _ _ _ _ _ _ _
SPLIT || START | COUNT || START | COUNT || SPLIT | TOTAL
_ _ _ _ _ _||_ _ _ _|_ _ _ _||_ _ _ _|_ _ _ _||_ _ _ _|_ _ _ _
Start || 0 | 114 || 0 | 114 || +0 | +0
Planet 1 || 114 | 2577 || 114 | 2115 || +462 | +462
Planet 12 || 2691 | 6581 || 2229 | 10203 || -3622 | -3160
Part Room || 9272 | 1710 || 12432 | 1791 || -81 | -3241
Boss || 10982 | 8343 || 16271 | 8343 || +0 | -3241
End || 19325 | - || 22566 | - || - | -3241
Software & Hardware
ROM
- Solar Jetman - Hunt for the Golden Warpship (USA).nes
- SHA1: CAA4D1AB710BD766F8505EF24F5702DAC6E988AF
- MD5: 45757BDF0D1A0E9DE8F9590FB692DA55
Emulator
Challenger: Neat discoveries! The game is breaking even further for the third time this year and excellent work again :)
